Question

I’m creating a List like this:
QList<Type> types[LastType];
Then I resize my list:
types[SomeType].reserve(count);
Then later on, when I try to add a type, I do this:
types[SomeType].append(newType);

And it’s giving me an asseration failure on operator[]. So, is it just me or i’m not supposed to be doing it like this? Is there something i’m missing? this is what the error message say: https://i.stack.imgur.com/Cy4uA.png . Removing .reserve does not fix the problem.

Answer 1

So, assuming a QList is really a vector under the hood, reserve is the wrong call. You’re not resizing your list as you say, you are asking it to allocate space for at least size more elements. Yes, it allocates more space, but it does not change the size of the list.

In any case, a call to this function never affects the elements contained in the vector, nor the vector size (for that purposes, see vector::resize or vector::erase, which modify the vector size and content).

Sounds like you want resize here.